The present invention relates to a blanket for dispensing an insulating particulate material onto the surface of a molten metal and to a method of using the blanket.
In the past, particulate materials have been applied to the surface of molten metals, e.g., in ladles and tundishes, in order to protect the molten metal from oxidation and provide heat insulation, thereby preventing the formation of a "skin" on the metal surface. Typically, it has been the practice to shovel loose or bulk material onto the surface of the metal to be insulated. A variety of particulate materials have been used in this manner, e.g., vermiculite, perlite, and rice hull ash.
This practice presents several disadvantages. When the particulate material is applied to the surface of the molten metal in a ladle, a great deal of dust may be generated and material is often spilled and wasted. Further, particulate material which is packaged in bulk is cumbersome and difficult to transport, store and dispense.
These difficulties have been somewhat alleviated by the practice of throwing bags of the particulate material onto the surface of the molten metal. These bags are typically of plastic or paper and thus decompose when they contact the molten metal. This practice tends to be uneconomical however, as the particulate material, rather than spreading out, tends to stay in a small area of the molten surface forming clumps of excess material. Thus it is necessary to use a large number of bags in order to adequately cover the entire molten surface. These bags of particulate material are also relatively difficult to store and transport using conventional methods, e.g., pallets.
Thus it has been desired to provide a means of dispensing an even layer of insulating particulate material onto the surface of molten metals without the above mentioned disadvantages.